Image recognition systems are commonly used in many contexts to efficiently identify matching objects between two or more images. Such systems often extract and compare distinctive features from the images to identify corresponding features within images. For example, fingerprint images can be compared and make an identification or verification decision based on comparing extracted minutiae. As another example, tattoo images can be compared to determine that two images either include the same tattoo present on a target's skin, or related tattoos of targets that have some affiliation represented by the related tattoos. In such examples, an image recognition system extracts color and/or grayscale characteristics from a search image and compares the extracted features to those of a set of previously collected reference images.